// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2001 Dave Engebretsen IBM Corporation
 */

#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/of.h>
#include <linux/fs.h>
#include <linux/reboot.h>
#include <linux/irq_work.h>

#include <asm/machdep.h>
#include <asm/rtas.h>
#include <asm/firmware.h>
#include <asm/mce.h>

#include "pseries.h"

static unsigned char ras_log_buf[RTAS_ERROR_LOG_MAX];
static DEFINE_SPINLOCK(ras_log_buf_lock);

static int ras_check_exception_token;

static void mce_process_errlog_event(struct irq_work *work);
static struct irq_work mce_errlog_process_work = {
        .func = mce_process_errlog_event,
};

#define EPOW_SENSOR_TOKEN       9
#define EPOW_SENSOR_INDEX       0

/* EPOW events counter variable */
static int num_epow_events;

static irqreturn_t ras_hotplug_interrupt(int irq, void *dev_id);
static irqreturn_t ras_epow_interrupt(int irq, void *dev_id);
static irqreturn_t ras_error_interrupt(int irq, void *dev_id);

/* RTAS pseries MCE errorlog section. */
struct pseries_mc_errorlog {
        __be32  fru_id;
        __be32  proc_id;
        u8      error_type;
        /*
         * sub_err_type (1 byte). Bit fields depends on error_type
         *
         *   MSB0
         *   |
         *   V
         *   01234567
         *   XXXXXXXX
         *
         * For error_type == MC_ERROR_TYPE_UE
         *   XXXXXXXX
         *   X          1: Permanent or Transient UE.
         *    X         1: Effective address provided.
         *     X        1: Logical address provided.
         *      XX      2: Reserved.
         *        XXX   3: Type of UE error.
         *
         * For error_type != MC_ERROR_TYPE_UE
         *   XXXXXXXX
         *   X          1: Effective address provided.
         *    XXXXX     5: Reserved.
         *         XX   2: Type of SLB/ERAT/TLB error.
         */
        u8      sub_err_type;
        u8      reserved_1[6];
        __be64  effective_address;
        __be64  logical_address;
} __packed;

/* RTAS pseries MCE error types */
#define MC_ERROR_TYPE_UE                0x00
#define MC_ERROR_TYPE_SLB               0x01
#define MC_ERROR_TYPE_ERAT              0x02
#define MC_ERROR_TYPE_UNKNOWN           0x03
#define MC_ERROR_TYPE_TLB               0x04
#define MC_ERROR_TYPE_D_CACHE           0x05
#define MC_ERROR_TYPE_I_CACHE           0x07

/* RTAS pseries MCE error sub types */
#define MC_ERROR_UE_INDETERMINATE               0
#define MC_ERROR_UE_IFETCH                      1
#define MC_ERROR_UE_PAGE_TABLE_WALK_IFETCH      2
#define MC_ERROR_UE_LOAD_STORE                  3
#define MC_ERROR_UE_PAGE_TABLE_WALK_LOAD_STORE  4

#define UE_EFFECTIVE_ADDR_PROVIDED              0x40
#define UE_LOGICAL_ADDR_PROVIDED                0x20

#define MC_ERROR_SLB_PARITY             0
#define MC_ERROR_SLB_MULTIHIT           1
#define MC_ERROR_SLB_INDETERMINATE      2

#define MC_ERROR_ERAT_PARITY            1
#define MC_ERROR_ERAT_MULTIHIT          2
#define MC_ERROR_ERAT_INDETERMINATE     3

#define MC_ERROR_TLB_PARITY             1
#define MC_ERROR_TLB_MULTIHIT           2
#define MC_ERROR_TLB_INDETERMINATE      3

static inline u8 rtas_mc_error_sub_type(const struct pseries_mc_errorlog *mlog)
{
        switch (mlog->error_type) {
        case    MC_ERROR_TYPE_UE:
                return (mlog->sub_err_type & 0x07);
        case    MC_ERROR_TYPE_SLB:
        case    MC_ERROR_TYPE_ERAT:
        case    MC_ERROR_TYPE_TLB:
                return (mlog->sub_err_type & 0x03);
        default:
                return 0;
        }
}

/*
 * Enable the hotplug interrupt late because processing them may touch other
 * devices or systems (e.g. hugepages) that have not been initialized at the
 * subsys stage.
 */
static int __init init_ras_hotplug_IRQ(void)
{
        struct device_node *np;

        /* Hotplug Events */
        np = of_find_node_by_path("/event-sources/hot-plug-events");
        if (np != NULL) {
                if (dlpar_workqueue_init() == 0)
                        request_event_sources_irqs(np, ras_hotplug_interrupt,
                                                   "RAS_HOTPLUG");
                of_node_put(np);
        }

        return 0;
}
machine_late_initcall(pseries, init_ras_hotplug_IRQ);

/*
 * Initialize handlers for the set of interrupts caused by hardware errors
 * and power system events.
 */
static int __init init_ras_IRQ(void)
{
        struct device_node *np;

        ras_check_exception_token = rtas_token("check-exception");

        /* Internal Errors */
        np = of_find_node_by_path("/event-sources/internal-errors");
        if (np != NULL) {
                request_event_sources_irqs(np, ras_error_interrupt,
                                           "RAS_ERROR");
                of_node_put(np);
        }

        /* EPOW Events */
        np = of_find_node_by_path("/event-sources/epow-events");
        if (np != NULL) {
                request_event_sources_irqs(np, ras_epow_interrupt, "RAS_EPOW");
                of_node_put(np);
        }

        return 0;
}
machine_subsys_initcall(pseries, init_ras_IRQ);

#define EPOW_SHUTDOWN_NORMAL                            1
#define EPOW_SHUTDOWN_ON_UPS                            2
#define EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS        3
#define EPOW_SHUTDOWN_AMBIENT_TEMPERATURE_TOO_HIGH      4

static void handle_system_shutdown(char event_modifier)
{
        switch (event_modifier) {
        case EPOW_SHUTDOWN_NORMAL:
                pr_emerg("Power off requested\n");
                orderly_poweroff(true);
                break;

        case EPOW_SHUTDOWN_ON_UPS:
                pr_emerg("Loss of system power detected. System is running on"
                         " UPS/battery. Check RTAS error log for details\n");
                break;

        case EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS:
                pr_emerg("Loss of system critical functions detected. Check"
                         " RTAS error log for details\n");
                orderly_poweroff(true);
                break;

        case EPOW_SHUTDOWN_AMBIENT_TEMPERATURE_TOO_HIGH:
                pr_emerg("High ambient temperature detected. Check RTAS"
                         " error log for details\n");
                orderly_poweroff(true);
                break;

        default:
                pr_err("Unknown power/cooling shutdown event (modifier = %d)\n",
                        event_modifier);
        }
}

struct epow_errorlog {
        unsigned char sensor_value;
        unsigned char event_modifier;
        unsigned char extended_modifier;
        unsigned char reserved;
        unsigned char platform_reason;
};

#define EPOW_RESET                      0
#define EPOW_WARN_COOLING               1
#define EPOW_WARN_POWER                 2
#define EPOW_SYSTEM_SHUTDOWN            3
#define EPOW_SYSTEM_HALT                4
#define EPOW_MAIN_ENCLOSURE             5
#define EPOW_POWER_OFF                  7

static void rtas_parse_epow_errlog(struct rtas_error_log *log)
{
        struct pseries_errorlog *pseries_log;
        struct epow_errorlog *epow_log;
        char action_code;
        char modifier;

        pseries_log = get_pseries_errorlog(log, PSERIES_ELOG_SECT_ID_EPOW);
        if (pseries_log == NULL)
                return;

        epow_log = (struct epow_errorlog *)pseries_log->data;
        action_code = epow_log->sensor_value & 0xF;     /* bottom 4 bits */
        modifier = epow_log->event_modifier & 0xF;      /* bottom 4 bits */

        switch (action_code) {
        case EPOW_RESET:
                if (num_epow_events) {
                        pr_info("Non critical power/cooling issue cleared\n");
                        num_epow_events--;
                }
                break;

        case EPOW_WARN_COOLING:
                pr_info("Non-critical cooling issue detected. Check RTAS error"
                        " log for details\n");
                break;

        case EPOW_WARN_POWER:
                pr_info("Non-critical power issue detected. Check RTAS error"
                        " log for details\n");
                break;

        case EPOW_SYSTEM_SHUTDOWN:
                handle_system_shutdown(modifier);
                break;

        case EPOW_SYSTEM_HALT:
                pr_emerg("Critical power/cooling issue detected. Check RTAS"
                         " error log for details. Powering off.\n");
                orderly_poweroff(true);
                break;

        case EPOW_MAIN_ENCLOSURE:
        case EPOW_POWER_OFF:
                pr_emerg("System about to lose power. Check RTAS error log "
                         " for details. Powering off immediately.\n");
                emergency_sync();
                kernel_power_off();
                break;

        default:
                pr_err("Unknown power/cooling event (action code  = %d)\n",
                        action_code);
        }

        /* Increment epow events counter variable */
        if (action_code != EPOW_RESET)
                num_epow_events++;
}

static irqreturn_t ras_hotplug_interrupt(int irq, void *dev_id)
{
        struct pseries_errorlog *pseries_log;
        struct pseries_hp_errorlog *hp_elog;

        spin_lock(&ras_log_buf_lock);

        rtas_call(ras_check_exception_token, 6, 1, NULL,
                  RTAS_VECTOR_EXTERNAL_INTERRUPT, virq_to_hw(irq),
                  RTAS_HOTPLUG_EVENTS, 0, __pa(&ras_log_buf),
                  rtas_get_error_log_max());

        pseries_log = get_pseries_errorlog((struct rtas_error_log *)ras_log_buf,
                                           PSERIES_ELOG_SECT_ID_HOTPLUG);
        hp_elog = (struct pseries_hp_errorlog *)pseries_log->data;

        /*
         * Since PCI hotplug is not currently supported on pseries, put PCI
         * hotplug events on the ras_log_buf to be handled by rtas_errd.
         */
        if (hp_elog->resource == PSERIES_HP_ELOG_RESOURCE_MEM ||
            hp_elog->resource == PSERIES_HP_ELOG_RESOURCE_CPU ||
            hp_elog->resource == PSERIES_HP_ELOG_RESOURCE_PMEM)
                queue_hotplug_event(hp_elog);
        else
                log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, 0);

        spin_unlock(&ras_log_buf_lock);
        return IRQ_HANDLED;
}

/* Handle environmental and power warning (EPOW) interrupts. */
static irqreturn_t ras_epow_interrupt(int irq, void *dev_id)
{
        int state;
        int critical;

        rtas_get_sensor_fast(EPOW_SENSOR_TOKEN, EPOW_SENSOR_INDEX, &state);

        if (state > 3)
                critical = 1;           /* Time Critical */
        else
                critical = 0;

        spin_lock(&ras_log_buf_lock);

        rtas_call(ras_check_exception_token, 6, 1, NULL, RTAS_VECTOR_EXTERNAL_INTERRUPT,
                  virq_to_hw(irq), RTAS_EPOW_WARNING, critical, __pa(&ras_log_buf),
                  rtas_get_error_log_max());

        log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, 0);

        rtas_parse_epow_errlog((struct rtas_error_log *)ras_log_buf);

        spin_unlock(&ras_log_buf_lock);
        return IRQ_HANDLED;
}

/*
 * Handle hardware error interrupts.
 *
 * RTAS check-exception is called to collect data on the exception.  If
 * the error is deemed recoverable, we log a warning and return.
 * For nonrecoverable errors, an error is logged and we stop all processing
 * as quickly as possible in order to prevent propagation of the failure.
 */
static irqreturn_t ras_error_interrupt(int irq, void *dev_id)
{
        struct rtas_error_log *rtas_elog;
        int status;
        int fatal;

        spin_lock(&ras_log_buf_lock);

        status = rtas_call(ras_check_exception_token, 6, 1, NULL,
                           RTAS_VECTOR_EXTERNAL_INTERRUPT,
                           virq_to_hw(irq),
                           RTAS_INTERNAL_ERROR, 1 /* Time Critical */,
                           __pa(&ras_log_buf),
                                rtas_get_error_log_max());

        rtas_elog = (struct rtas_error_log *)ras_log_buf;

        if (status == 0 &&
            rtas_error_severity(rtas_elog) >= RTAS_SEVERITY_ERROR_SYNC)
                fatal = 1;
        else
                fatal = 0;

        /* format and print the extended information */
        log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, fatal);

        if (fatal) {
                pr_emerg("Fatal hardware error detected. Check RTAS error"
                         " log for details. Powering off immediately\n");
                emergency_sync();
                kernel_power_off();
        } else {
                pr_err("Recoverable hardware error detected\n");
        }

        spin_unlock(&ras_log_buf_lock);
        return IRQ_HANDLED;
}

/*
 * Some versions of FWNMI place the buffer inside the 4kB page starting at
 * 0x7000. Other versions place it inside the rtas buffer. We check both.
 * Minimum size of the buffer is 16 bytes.
 */
#define VALID_FWNMI_BUFFER(A) \
        ((((A) >= 0x7000) && ((A) <= 0x8000 - 16)) || \
        (((A) >= rtas.base) && ((A) <= (rtas.base + rtas.size - 16))))

static inline struct rtas_error_log *fwnmi_get_errlog(void)
{
        return (struct rtas_error_log *)local_paca->mce_data_buf;
}

static __be64 *fwnmi_get_savep(struct pt_regs *regs)
{
        unsigned long savep_ra;

        /* Mask top two bits */
        savep_ra = regs->gpr[3] & ~(0x3UL << 62);
        if (!VALID_FWNMI_BUFFER(savep_ra)) {
                printk(KERN_ERR "FWNMI: corrupt r3 0x%016lx\n", regs->gpr[3]);
                return NULL;
        }

        return __va(savep_ra);
}

/*
 * Get the error information for errors coming through the
 * FWNMI vectors.  The pt_regs' r3 will be updated to reflect
 * the actual r3 if possible, and a ptr to the error log entry
 * will be returned if found.
 *
 * Use one buffer mce_data_buf per cpu to store RTAS error.
 *
 * The mce_data_buf does not have any locks or protection around it,
 * if a second machine check comes in, or a system reset is done
 * before we have logged the error, then we will get corruption in the
 * error log.  This is preferable over holding off on calling
 * ibm,nmi-interlock which would result in us checkstopping if a
 * second machine check did come in.
 */
static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs)
{
        struct rtas_error_log *h;
        __be64 *savep;

        savep = fwnmi_get_savep(regs);
        if (!savep)
                return NULL;

        regs->gpr[3] = be64_to_cpu(savep[0]); /* restore original r3 */

        h = (struct rtas_error_log *)&savep[1];
        /* Use the per cpu buffer from paca to store rtas error log */
        memset(local_paca->mce_data_buf, 0, RTAS_ERROR_LOG_MAX);
        if (!rtas_error_extended(h)) {
                memcpy(local_paca->mce_data_buf, h, sizeof(__u64));
        } else {
                int len, error_log_length;

                error_log_length = 8 + rtas_error_extended_log_length(h);
                len = min_t(int, error_log_length, RTAS_ERROR_LOG_MAX);
                memcpy(local_paca->mce_data_buf, h, len);
        }

        return (struct rtas_error_log *)local_paca->mce_data_buf;
}

/* Call this when done with the data returned by FWNMI_get_errinfo.
 * It will release the saved data area for other CPUs in the
 * partition to receive FWNMI errors.
 */
static void fwnmi_release_errinfo(void)
{
        struct rtas_args rtas_args;
        int ret;

        /*
         * On pseries, the machine check stack is limited to under 4GB, so
         * args can be on-stack.
         */
        rtas_call_unlocked(&rtas_args, ibm_nmi_interlock_token, 0, 1, NULL);
        ret = be32_to_cpu(rtas_args.rets[0]);
        if (ret != 0)
                printk(KERN_ERR "FWNMI: nmi-interlock failed: %d\n", ret);
}

int pSeries_system_reset_exception(struct pt_regs *regs)
{
#ifdef __LITTLE_ENDIAN__
        /*
         * Some firmware byteswaps SRR registers and gives incorrect SRR1. Try
         * to detect the bad SRR1 pattern here. Flip the NIP back to correct
         * endian for reporting purposes. Unfortunately the MSR can't be fixed,
         * so clear it. It will be missing MSR_RI so we won't try to recover.
         */
        if ((be64_to_cpu(regs->msr) &
                        (MSR_LE|MSR_RI|MSR_DR|MSR_IR|MSR_ME|MSR_PR|
                         MSR_ILE|MSR_HV|MSR_SF)) == (MSR_DR|MSR_SF)) {
                regs_set_return_ip(regs, be64_to_cpu((__be64)regs->nip));
                regs_set_return_msr(regs, 0);
        }
#endif

        if (fwnmi_active) {
                __be64 *savep;

                /*
                 * Firmware (PowerVM and KVM) saves r3 to a save area like
                 * machine check, which is not exactly what PAPR (2.9)
                 * suggests but there is no way to detect otherwise, so this
                 * is the interface now.
                 *
                 * System resets do not save any error log or require an
                 * "ibm,nmi-interlock" rtas call to release.
                 */

                savep = fwnmi_get_savep(regs);
                if (savep)
                        regs->gpr[3] = be64_to_cpu(savep[0]); /* restore original r3 */
        }

        if (smp_handle_nmi_ipi(regs))
                return 1;

        return 0; /* need to perform reset */
}

static int mce_handle_err_realmode(int disposition, u8 error_type)
{
#ifdef CONFIG_PPC_BOOK3S_64
        if (disposition == RTAS_DISP_NOT_RECOVERED) {
                switch (error_type) {
                case    MC_ERROR_TYPE_ERAT:
                        flush_erat();
                        disposition = RTAS_DISP_FULLY_RECOVERED;
                        break;
                case    MC_ERROR_TYPE_SLB:
                        /*
                         * Store the old slb content in paca before flushing.
                         * Print this when we go to virtual mode.
                         * There are chances that we may hit MCE again if there
                         * is a parity error on the SLB entry we trying to read
                         * for saving. Hence limit the slb saving to single
                         * level of recursion.
                         */
                        if (local_paca->in_mce == 1)
                                slb_save_contents(local_paca->mce_faulty_slbs);
                        flush_and_reload_slb();
                        disposition = RTAS_DISP_FULLY_RECOVERED;
                        break;
                default:
                        break;
                }
        } else if (disposition == RTAS_DISP_LIMITED_RECOVERY) {
                /* Platform corrected itself but could be degraded */
                pr_err("MCE: limited recovery, system may be degraded\n");
                disposition = RTAS_DISP_FULLY_RECOVERED;
        }
#endif
        return disposition;
}

static int mce_handle_err_virtmode(struct pt_regs *regs,
                                   struct rtas_error_log *errp,
                                   struct pseries_mc_errorlog *mce_log,
                                   int disposition)
{
        struct mce_error_info mce_err = { 0 };
        int initiator = rtas_error_initiator(errp);
        int severity = rtas_error_severity(errp);
        unsigned long eaddr = 0, paddr = 0;
        u8 error_type, err_sub_type;

        if (!mce_log)
                goto out;

        error_type = mce_log->error_type;
        err_sub_type = rtas_mc_error_sub_type(mce_log);

        if (initiator == RTAS_INITIATOR_UNKNOWN)
                mce_err.initiator = MCE_INITIATOR_UNKNOWN;
        else if (initiator == RTAS_INITIATOR_CPU)
                mce_err.initiator = MCE_INITIATOR_CPU;
        else if (initiator == RTAS_INITIATOR_PCI)
                mce_err.initiator = MCE_INITIATOR_PCI;
        else if (initiator == RTAS_INITIATOR_ISA)
                mce_err.initiator = MCE_INITIATOR_ISA;
        else if (initiator == RTAS_INITIATOR_MEMORY)
                mce_err.initiator = MCE_INITIATOR_MEMORY;
        else if (initiator == RTAS_INITIATOR_POWERMGM)
                mce_err.initiator = MCE_INITIATOR_POWERMGM;
        else
                mce_err.initiator = MCE_INITIATOR_UNKNOWN;

        if (severity == RTAS_SEVERITY_NO_ERROR)
                mce_err.severity = MCE_SEV_NO_ERROR;
        else if (severity == RTAS_SEVERITY_EVENT)
                mce_err.severity = MCE_SEV_WARNING;
        else if (severity == RTAS_SEVERITY_WARNING)
                mce_err.severity = MCE_SEV_WARNING;
        else if (severity == RTAS_SEVERITY_ERROR_SYNC)
                mce_err.severity = MCE_SEV_SEVERE;
        else if (severity == RTAS_SEVERITY_ERROR)
                mce_err.severity = MCE_SEV_SEVERE;
        else
                mce_err.severity = MCE_SEV_FATAL;

        if (severity <= RTAS_SEVERITY_ERROR_SYNC)
                mce_err.sync_error = true;
        else
                mce_err.sync_error = false;

        mce_err.error_type = MCE_ERROR_TYPE_UNKNOWN;
        mce_err.error_class = MCE_ECLASS_UNKNOWN;

        switch (error_type) {
        case MC_ERROR_TYPE_UE:
                mce_err.error_type = MCE_ERROR_TYPE_UE;
                mce_common_process_ue(regs, &mce_err);
                if (mce_err.ignore_event)
                        disposition = RTAS_DISP_FULLY_RECOVERED;
                switch (err_sub_type) {
                case MC_ERROR_UE_IFETCH:
                        mce_err.u.ue_error_type = MCE_UE_ERROR_IFETCH;
                        break;
                case MC_ERROR_UE_PAGE_TABLE_WALK_IFETCH:
                        mce_err.u.ue_error_type = MCE_UE_ERROR_PAGE_TABLE_WALK_IFETCH;
                        break;
                case MC_ERROR_UE_LOAD_STORE:
                        mce_err.u.ue_error_type = MCE_UE_ERROR_LOAD_STORE;
                        break;
                case MC_ERROR_UE_PAGE_TABLE_WALK_LOAD_STORE:
                        mce_err.u.ue_error_type = MCE_UE_ERROR_PAGE_TABLE_WALK_LOAD_STORE;
                        break;
                case MC_ERROR_UE_INDETERMINATE:
                default:
                        mce_err.u.ue_error_type = MCE_UE_ERROR_INDETERMINATE;
                        break;
                }
                if (mce_log->sub_err_type & UE_EFFECTIVE_ADDR_PROVIDED)
                        eaddr = be64_to_cpu(mce_log->effective_address);

                if (mce_log->sub_err_type & UE_LOGICAL_ADDR_PROVIDED) {
                        paddr = be64_to_cpu(mce_log->logical_address);
                } else if (mce_log->sub_err_type & UE_EFFECTIVE_ADDR_PROVIDED) {
                        unsigned long pfn;

                        pfn = addr_to_pfn(regs, eaddr);
                        if (pfn != ULONG_MAX)
                                paddr = pfn << PAGE_SHIFT;
                }

                break;
        case MC_ERROR_TYPE_SLB:
                mce_err.error_type = MCE_ERROR_TYPE_SLB;
                switch (err_sub_type) {
                case MC_ERROR_SLB_PARITY:
                        mce_err.u.slb_error_type = MCE_SLB_ERROR_PARITY;
                        break;
                case MC_ERROR_SLB_MULTIHIT:
                        mce_err.u.slb_error_type = MCE_SLB_ERROR_MULTIHIT;
                        break;
                case MC_ERROR_SLB_INDETERMINATE:
                default:
                        mce_err.u.slb_error_type = MCE_SLB_ERROR_INDETERMINATE;
                        break;
                }
                if (mce_log->sub_err_type & 0x80)
                        eaddr = be64_to_cpu(mce_log->effective_address);
                break;
        case MC_ERROR_TYPE_ERAT:
                mce_err.error_type = MCE_ERROR_TYPE_ERAT;
                switch (err_sub_type) {
                case MC_ERROR_ERAT_PARITY:
                        mce_err.u.erat_error_type = MCE_ERAT_ERROR_PARITY;
                        break;
                case MC_ERROR_ERAT_MULTIHIT:
                        mce_err.u.erat_error_type = MCE_ERAT_ERROR_MULTIHIT;
                        break;
                case MC_ERROR_ERAT_INDETERMINATE:
                default:
                        mce_err.u.erat_error_type = MCE_ERAT_ERROR_INDETERMINATE;
                        break;
                }
                if (mce_log->sub_err_type & 0x80)
                        eaddr = be64_to_cpu(mce_log->effective_address);
                break;
        case MC_ERROR_TYPE_TLB:
                mce_err.error_type = MCE_ERROR_TYPE_TLB;
                switch (err_sub_type) {
                case MC_ERROR_TLB_PARITY:
                        mce_err.u.tlb_error_type = MCE_TLB_ERROR_PARITY;
                        break;
                case MC_ERROR_TLB_MULTIHIT:
                        mce_err.u.tlb_error_type = MCE_TLB_ERROR_MULTIHIT;
                        break;
                case MC_ERROR_TLB_INDETERMINATE:
                default:
                        mce_err.u.tlb_error_type = MCE_TLB_ERROR_INDETERMINATE;
                        break;
                }
                if (mce_log->sub_err_type & 0x80)
                        eaddr = be64_to_cpu(mce_log->effective_address);
                break;
        case MC_ERROR_TYPE_D_CACHE:
                mce_err.error_type = MCE_ERROR_TYPE_DCACHE;
                break;
        case MC_ERROR_TYPE_I_CACHE:
                mce_err.error_type = MCE_ERROR_TYPE_ICACHE;
                break;
        case MC_ERROR_TYPE_UNKNOWN:
        default:
                mce_err.error_type = MCE_ERROR_TYPE_UNKNOWN;
                break;
        }
out:
        save_mce_event(regs, disposition == RTAS_DISP_FULLY_RECOVERED,
                       &mce_err, regs->nip, eaddr, paddr);
        return disposition;
}

static int mce_handle_error(struct pt_regs *regs, struct rtas_error_log *errp)
{
        struct pseries_errorlog *pseries_log;
        struct pseries_mc_errorlog *mce_log = NULL;
        int disposition = rtas_error_disposition(errp);
        unsigned long msr;
        u8 error_type;

        if (!rtas_error_extended(errp))
                goto out;

        pseries_log = get_pseries_errorlog(errp, PSERIES_ELOG_SECT_ID_MCE);
        if (!pseries_log)
                goto out;

        mce_log = (struct pseries_mc_errorlog *)pseries_log->data;
        error_type = mce_log->error_type;

        disposition = mce_handle_err_realmode(disposition, error_type);

        /*
         * Enable translation as we will be accessing per-cpu variables
         * in save_mce_event() which may fall outside RMO region, also
         * leave it enabled because subsequently we will be queuing work
         * to workqueues where again per-cpu variables accessed, besides
         * fwnmi_release_errinfo() crashes when called in realmode on
         * pseries.
         * Note: All the realmode handling like flushing SLB entries for
         *       SLB multihit is done by now.
         */
out:
        msr = mfmsr();
        mtmsr(msr | MSR_IR | MSR_DR);

        disposition = mce_handle_err_virtmode(regs, errp, mce_log,
                                              disposition);

        /*
         * Queue irq work to log this rtas event later.
         * irq_work_queue uses per-cpu variables, so do this in virt
         * mode as well.
         */
        irq_work_queue(&mce_errlog_process_work);

        mtmsr(msr);

        return disposition;
}

/*
 * Process MCE rtas errlog event.
 */
static void mce_process_errlog_event(struct irq_work *work)
{
        struct rtas_error_log *err;

        err = fwnmi_get_errlog();
        log_error((char *)err, ERR_TYPE_RTAS_LOG, 0);
}

/*
 * See if we can recover from a machine check exception.
 * This is only called on power4 (or above) and only via
 * the Firmware Non-Maskable Interrupts (fwnmi) handler
 * which provides the error analysis for us.
 *
 * Return 1 if corrected (or delivered a signal).
 * Return 0 if there is nothing we can do.
 */
static int recover_mce(struct pt_regs *regs, struct machine_check_event *evt)
{
        int recovered = 0;

        if (regs_is_unrecoverable(regs)) {
                /* If MSR_RI isn't set, we cannot recover */
                pr_err("Machine check interrupt unrecoverable: MSR(RI=0)\n");
                recovered = 0;
        } else if (evt->disposition == MCE_DISPOSITION_RECOVERED) {
                /* Platform corrected itself */
                recovered = 1;
        } else if (evt->severity == MCE_SEV_FATAL) {
                /* Fatal machine check */
                pr_err("Machine check interrupt is fatal\n");
                recovered = 0;
        }

        if (!recovered && evt->sync_error) {
                /*
                 * Try to kill processes if we get a synchronous machine check
                 * (e.g., one caused by execution of this instruction). This
                 * will devolve into a panic if we try to kill init or are in
                 * an interrupt etc.
                 *
                 * TODO: Queue up this address for hwpoisioning later.
                 * TODO: This is not quite right for d-side machine
                 *       checks ->nip is not necessarily the important
                 *       address.
                 */
                if ((user_mode(regs))) {
                        _exception(SIGBUS, regs, BUS_MCEERR_AR, regs->nip);
                        recovered = 1;
                } else if (die_will_crash()) {
                        /*
                         * die() would kill the kernel, so better to go via
                         * the platform reboot code that will log the
                         * machine check.
                         */
                        recovered = 0;
                } else {
                        die_mce("Machine check", regs, SIGBUS);
                        recovered = 1;
                }
        }

        return recovered;
}

/*
 * Handle a machine check.
 *
 * Note that on Power 4 and beyond Firmware Non-Maskable Interrupts (fwnmi)
 * should be present.  If so the handler which called us tells us if the
 * error was recovered (never true if RI=0).
 *
 * On hardware prior to Power 4 these exceptions were asynchronous which
 * means we can't tell exactly where it occurred and so we can't recover.
 */
int pSeries_machine_check_exception(struct pt_regs *regs)
{
        struct machine_check_event evt;

        if (!get_mce_event(&evt, MCE_EVENT_RELEASE))
                return 0;

        /* Print things out */
        if (evt.version != MCE_V1) {
                pr_err("Machine Check Exception, Unknown event version %d !\n",
                       evt.version);
                return 0;
        }
        machine_check_print_event_info(&evt, user_mode(regs), false);

        if (recover_mce(regs, &evt))
                return 1;

        return 0;
}

long pseries_machine_check_realmode(struct pt_regs *regs)
{
        struct rtas_error_log *errp;
        int disposition;

        if (fwnmi_active) {
                errp = fwnmi_get_errinfo(regs);
                /*
                 * Call to fwnmi_release_errinfo() in real mode causes kernel
                 * to panic. Hence we will call it as soon as we go into
                 * virtual mode.
                 */
                disposition = mce_handle_error(regs, errp);

                fwnmi_release_errinfo();

                if (disposition == RTAS_DISP_FULLY_RECOVERED)
                        return 1;
        }

        return 0;
}